This invention relates to a self-closing closure for tubes and other containers in which the pressure in the container may be manually varied, preferably by squeezing the container to a less or greater extent. More specifically, the invention relates to a closure in which said pressure variation causes automatic opening of the closure.
A known closure of this kind has a bellows shape and comprises two suitably disc-shaped members connected to each other along the outer portions thereof. The inner portions of the members together form a valve device in which a dowel connected to the first member operates as a stop valve against an opening serving as a valve seat in the second member. In such closure the concave sides of the disc-shaped members face each other.
Said previously known closure operates well, especially when dispensing relatively thin flowing substances but is less suitable in the case of higher-viscosity substances because the required opening pressure is relatively high.